A rotating electric machine includes a stator coil assembly having multiple stator coils. Machines incorporating high temperature superconductor (HTS) stator materials experience a significant increase in the field electromotive forces generated by the windings and increased flux and power densities of the machines as compared to conventional “non-superconducting” rotating machines incorporating iron-toothed stators. Furthermore, in HTS based electrical machines, the stator coils are the sole recipients of the Lorenz magnetic force, in contrast to conventional stators where most of the force is dissipated through the iron teeth.
The stator coils are positioned radially about the perimeter of a cylindrical support structure. The desired number of magnetic poles dictates the number of stator coils included in the assembly. “Racetrack” type stator coils have two straight sections disposed parallel to a center axis of the cylindrical support structure and two end turn regions linking the straight sections. The straight sections are the active sections through which current must flow to electromagnetically engage a rotor assembly, causing it to rotate.
In addition to the heat generated by the rotor assembly, the stator assembly also generates a considerable amount of heat that must be removed in order for the superconducting machine to operate efficiently. In conventional “non-superconducting” rotating machines, iron teeth are utilized between the individual stator coil assemblies, which act as heat sinks and remove the heat generated by the stator assembly. However, in superconducting machines, the flux density is so great between these stator coil assemblies that these iron teeth would immediately become saturated, resulting in Eddy current heating and operating inefficiency.